Impact of Protein Intake on eGFR Slope One Year Post Kidney Transplantation: A Single- center Retrospective Study

Impact of Protein Intake on eGFR Slope One Year Post Kidney Transplantation: A Single- center Retrospective Study | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Impact of Protein Intake on eGFR Slope One Year Post Kidney Transplantation: A Single- center Retrospective Study Tetsuya Abe, Togo Aoyama, Keiichi Matsuzaki, Yuko Morioka, Tomoko Yoshida, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7148397/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background The optimal protein intake following kidney transplantation remains unclear. The rate of change in kidney function during the first year post-transplant is considered a predictor of the subsequent survival and graft survival rates. This study aimed to determine the effect of evaluating protein intake during the first year post-transplant on kidney function at 1 year. Methods This retrospective study included 90 patients who underwent kidney transplantation. Patients were classified into three groups based on average daily protein intake: low (< 0.9 g/kg ideal body weight (IBW)/day), middle (≥ 0.9 and < 1.2 g/kg IBW/day) IBW/day), high (≥ 1.2 g/kg IBW/day). The primary outcome was the eGFR slope at 1 year after transplantation, and the secondary outcome was the incidence of rapid eGFR decline at 1 year after transplantation. Results Mean eGFR slope (mL/min/1.73 m 2 /year) at 1 year after kidney transplantation was − 0.89, 2.44, and − 3.56 in the low, middle, and high protein intake groups, respectively (p = 0.01). Low protein intake had a greater effect than middle protein intake on eGFR slope decline (odds ratio (OR) 3.12, 95% confidence interval (CI) 1.24–7.84, p = 0.02). Rapid eGFR slope decline was more common in the high protein intake group (62.5%, p < 0.01) and high protein intake was a greater risk factor than middle protein intake (OR 22.4, 95%CI 3.21–157, p < 0.01). Conclusions Both low and high protein intake may adversely affect kidney function at 1 year after kidney transplantation. Evaluating protein intake during the first year post-transplant may help optimize eGFR at the 1-year mark. kidney transplantation protein intake eGFR slope kidney graft function Figures Figure 1 Figure 2 Figure 3 Background Kidney transplantation is widely recognized as the best treatment for patients with end-stage kidney failure. In Japan, approximately 90% of kidney transplants are performed using organs from living donors, with the remainder from deceased donors. The waiting period is approximately 15 years for a deceased kidney transplant, underscoring the serious shortage of available donors. Therefore, it is desirable that recipients maintain optimal kidney function following transplantation. As the number of kidney transplant patients in Japan continues to increase annually, comprehensive management aimed at preventing rejection and infection that also addresses nutritional care is crucial for maintaining optimal kidney function thereafter. In addition, regular nutritional guidance from dietitians has been shown to mitigate decline in post-transplant estimated glomerular filtration rate (eGFR)[ 1 ]. It is well established that protein restriction is essential for patients with chronic kidney disease (CKD). However, excessive protein restriction can lead to chronic inflammation, oxidative stress, and muscle weakness, potentially worsening both kidney function and overall prognosis[ 2 , 3 ]. In contrast, excessive protein intake has been shown to cause hyperfiltration, in both human and animal experiments[ 4 – 7 ]. Post-transplant kidney function improves dramatically, often approaching Grade 3b. Nevertheless, the optimal level of protein restriction after kidney transplantation has not yet been established, and its effectiveness remains unclear. Clayton et al. reported that the rate of change in eGFR in the first year after kidney transplantation is a predictor of patient survival and graft survival[ 8 ] [ 9 ], and eGFR slope has recently been suggested as a surrogate endpoint for predicting kidney prognosis [ 2 ] [ 10 ]. Therefore, it is important to investigate the risk factors associated with kidney dysfunction in the first year after kidney transplantation. We hypothesized that both excessive protein restriction and high protein intake after kidney transplantation would adversely affect graft kidney function, similar to those observed in CKD. The purpose of this study was to evaluate the effect of protein intake during the first year after kidney transplantation on kidney function at 1 year. Methods Study Design This study included 150 kidney transplant patients aged ≥ 18 years who underwent kidney transplantation at Kitasato university hospital between 1 January 2009 and 1 February 2020. The exclusion criteria were age < 18 years, loss to follow-up within 1 year after kidney transplantation, rejection within 1 year after kidney transplantation, and patients who received a deceased donor kidney transplant. After excluding 60 patients, a final total of 90 patients were retrospectively observed (Fig. 1 ). This clinical study was approved by the Ethics Committee (approval No. B24-175). The study was conducted in accordance with the Declaration of Helsinki and adhered to the principles of the Declaration of Istanbul as outlined in the Declaration of Istanbul on Organ Trafficking and Transplant Tourism. Measurements The clinical features and laboratory results of recipients during hospitalization for kidney transplant surgery were used as the baseline values. Clinical characteristics included age at transplantation, sex, BMI at discharge, preemptive kidney transplantation rate, primary disease leading to kidney failure, types and concentrations of immunosuppressive medications, percentage of rituximab use, duration of dialysis, percentage of blood-type-matched or incompatible transplants, number of HLA mismatches, and mean systolic and diastolic blood pressures. Donor kidney weight, warm ischemic time, cold ischemic time, and total ischemic time were also evaluated. Mean blood pressure was calculated from blood pressure measurements taken during outpatient visits at 1, 3, 6, 9, and 12 months after kidney transplantation. The following blood test results were evaluated: hemoglobin, hematocrit, serum albumin, serum creatinine, eGFR, blood urea nitrogen (BUN), low-density lipoprotein (LDL), hemoglobin A1c (HbA1c), C-reactive protein (CRP). Results from Day 21 after surgery were used for evaluation of serum creatinine and eGFR. For LDL, HbA1c, and CRP, the results during hospitalization for kidney transplantation were used. The use of angiotensin II receptor blocker (ARB) within 1 year was also evaluated. Immunosuppression The standard maintenance immunosuppressants used were steroids, calcineurin inhibitors (tacrolimus [TAC] or cyclosporine [CsA])), and metabolic antagonists (mycophenolate mofetil [MMF] and/or everolimus [EVR] and/or mizoribine). In all cases, a steroid (methylprednisolone, 250 mg intravenously) was administered prior to surgery, intraoperatively, and on the day following surgery. Basiliximab was also administered in all cases. The target levels of immunosuppressive drugs used at our hospital during the study period were as follows. The TAC extended-release target trough level was 7–8 ng/mL, after which the maintenance dose was reduced to achieve 5–6 ng/mL. Mycophenolate mofetil was adjusted to achieve a target area under the concentration–time curve of 40–80 µg·h/mL during the first 4 hours after administration. The target C2 level for CsA was 800–1000 ng/mL for the first 3 months, after which the maintenance dose was reduced to achieve 600–800 ng/mL. EVR was adjusted to achieve a trough level of 3–5 ng/mL. Prednisolone was started at a dose of 30 mg/day and subsequently reduced to 5 mg/day at 3 weeks after kidney transplantation. Definitions for grouping and study outcomes Protein intake in the year following transplantation was estimated from 24-hour urine collection using Maroni’s formula. Protein intake was calculated as the mean daily protein intake from 24-hour urine collection at 3, 6, 9, and 12 months after transplantation. Patients with an average daily protein intake of < 0.9 g/kg IBW/day were assigned to the low protein intake group, those with ≥ 0.9 and < 1.2 g/kg IBW/day were assigned to the middle protein intake group, and those with ≥ 1.2 g/kg IBW/day were assigned to the high protein intake group (Supplementary table 1 , Supplementary Figs. 1, 2). The primary outcome was eGFR slope in the first year after transplantation. eGFR slope was calculated by plotting the eGFR measurements at each time point during the first year after transplantation, deriving a linear approximation equation, and using the slope of the resulting line to represent the annual rate of change. The secondary outcome was the incidence of rapid eGFR decline, defined as a decrease of > 5 mL/min/1.73 m 2 /year [ 11 ]. Statistical Analysis Data for normally distributed continuous variables are presented as mean ± standard deviation, and data for non-normally distributed continuous variables are presented as median (interquartile range). The χ 2 test, one-way ANOVA, and Kruskal–Wallis test were used for comparisons among the three groups. Dunnett’s test was used for multiple comparisons. Binomial logistic analysis was performed to evaluate predictors of the eGFR slope at 1 year after kidney transplantation and predictors of eGFR slope decline, and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. All statistical analyses were performed using GraphPad Prism version 10.2.0 for Windows (GraphPad Software, Boston, MA; www.graphpad.com ). All tests were two-sided, and p < 0.05 was considered statistically significant. All CIs were calculated at the 95% confidence level. Results Patient characteristics Of the 150 patients admitted to the study, 90 were followed up for 1 year after transplantation (41, 41, and 8 in the middle, low, and high protein intake groups, respectively). There were no differences among the groups in terms of age at the time of kidney transplantation, sex, duration of dialysis, or use of ARB. The rate of diabetes mellitus (DM) as the primary disease was highest in the high protein intake group and lowest in the low protein intake group. BMI was significantly the lowest in the low protein intake group. Mean systolic blood pressure was highest in the high protein intake group. There was no significant difference in diastolic blood pressure among the groups. Regarding donor factors, there were no differences in kidney weight or ischemic time among the groups. There was no difference in trough TAC level at 6 months after transplantation among the groups (Table 1 ). There was no significant difference in median eGFR at 21 days after transplantation among the groups (44.0 [32.2–47.3] in the low protein intake group versus 39.0 [29.0–44.8] in the middle protein intake group versus 37.1 [28.0–56.6] in the low protein intake group; p = 0.33; Fig. 2 ). There were no significant differences in Hb, LDL, HbA1c, or CRP among the groups (Table 1 ). Table 1 Patient characteristics Low protein intake group (n = 41) Middle protein intake group (n = 41) High protein intake group (n = 8) P-value Characteristic Age at transplantation (years) 43.2 (± 15.2) 45.8 (± 14.3) 48.1 (± 13.2) 0.58 Male sex (%) 25 (61) 28 (68.3) 5 (62.5) 0.78 PEKT (%) 5 (12.2) 9 (22.0) 0 (0) 0.21 BMI (kg/m²) 18.9 (16.8–20.9) 21.4 (19.4–22.9) 21.0 (18.7–28.0) 0.003 Dialysis period (months) 20 (3.5–90) 10 (1.0-34.5) 29 (7.5–53.0) 0.3 Blood-group-compatible transplant (%) 31 (75.6) 31 (75.6) 7 (87.5) 0.75 HLA mismatch 3.0 (2.5-4.0) 3.0 (2.0-4.5) 3.5 (3.0-4.75) 0.38 Kidney weight (g) 180 (170-223.8) 175 (147.8–200) 187.5 (181.3-233.8) 0.07 WIT (min) 5.0 (4.0–6.0) 5.0 (4.0–6.0) 4.5 (3.25-5.0) 0.22 CIT (min) 72.0 (58.0–96.0) 70.0 (63.0-90.8) 57.5 (42.5–74.0) 0.1 TIT (min) 76.0 (63.5-101.5) 77.0 (67.3–96.8) 62.0 (46.8–78.3) 0.07 Mean systolic blood pressure (mmHg) 121.6 (111.7-130.1) 126.0 (119.6-130.3) 131.7 (124.4-137.2) 0.04 Mean diastolic blood pressure (mmHg) 75.0 (70.6–80.6) 77.6 (71.3–82.1) 76.9 (71.5–81.1) 0.54 Hemoglobin (g/dL) 10.4 (9.2–11.5) 10.2 (8.95–11.5) 9.95 (8.78-11.0) 0.57 Hematocrit (%) 32.1 (28.8–35.2) 31.6 (29.5–35.6) 29.9 (26.4–33.1) 0.39 Serum albumin (g/dL) 3.9 (3.7–4.3) 3.9 (3.75–4.25) 3.85 (3.55–4.30) 0.83 Serum creatinine (mg/dL) 1.47 (1.12–1.68) 1.46 (1.28–1.96) 1.47 (1.03–2.13) 0.68 eGFR (mL/min/1.73 m²) 44.0 (32.2–47.3) 39.0 (29.0-44.8) 37.1 (28.0-56.6) 0.33 BUN (mg/dL) 17.1 (12.7–20.3) 18.9 (15.0-21.4) 17.3 (10.3–21.9) 0.43 LDL (mg/dL) 107 (87–118) 93 (81-113.5) 87.5 (74.3–102) 0.19 HbA1c (%) 5.4 (5.2–5.8) 5.6 (5.1–6.2) 5.6 (5.1–6.4) 0.72 CRP (mg/dL) 0.07 (0.03–0.45) 0.07 (0.03–0.15) 0.03 (0.03–0.16) 0.33 Use of ARB within 1 year 17 (41.5) 16 (39.0) 1 (12.5) 0.3 Diagnosis DM (%) 2 (4.9) 7 (17.1) 3 (37.5) 0.03 CGN (%) 23 (56.1) 21 (51.2) 3 (37.5) 0.62 ADPKD (%) 1 (2.4) 2 (4.9) 1 (12.5) 0.44 Renal sclerosis (%) 3 (7.3) 1 (2.4) 0 (0) 0.46 Other (%) 12 (29.3) 10 (24.4) 1 (12.5) 0.59 Immunosuppression TAC/CsA (%) 37 (90.2)/ 4 (9.8) 41 (100)/ 0 (0) 7 (87.5)/ 1 (12.5) 0.1 MMF (%) 38 (92.7) 38 (92.7) 7 (87.5) 0.87 EVR (%) 11 (26.8) 8 (19.5) 3 (37.5) 0.5 MZB (%) 3 (7.3) 1 (2.4) 1 (12.5) 0.42 Rituximab (%) 14 (34.1) 13 (31.7) 1 (12.5) 0.48 MMF dose at 6 months 1000 (1000–1000) 1000 (937.5–1000) 1000 (500–1000) 0.89 Concentration level TAC trough (ng/mL) 4.80 (3.90–6.50) 4.80 (3.70–6.05) 3.60 (2.30–4.70) 0.23 CsA C2 level (ng/mL) 255 (115.0-257.0) - 151.0 (151.0-151.0) - Abbreviations: PEKT preemptive kidney transplantation, BMI body mass index, HLA human leukocyte antigen, WIT warm ischemic time, CIT cold ischemic time, TIT total ischemic time, eGFR estimated glomerular filtration rate, BUN blood urea nitrogen, LDL low-density lipoprotein, HbA1c hemoglobin A1c, CRP c-reactive protein, ARB angiotensin receptor blocker, DM diabetes mellitus, CGN chronic glomerular nephritis, ADPKD autosomal dominant polycystic kidney disease, TAC tacrolimus, CsA cyclosporine, MMF mycophenolate mofetil, EVR everolimus, MZB mizoribine Outcomes Mean eGFR slope (mL/min/1.73 m 2 /year) at 1 year after living donor kidney transplantation was − 0.89 (± 7.12) in the low protein intake group, 2.44 (± 6.57) in the middle protein intake group, and − 3.56 (± 7.28) in the high protein intake group. Mean eGFR slope did not decline in the middle protein intake group but declined in both the low and high protein intake groups (p < 0.05; Table 2 , Fig. 3 ). Dunnett’s test for multiple comparisons found a significant difference in eGFR slope decline in both the low and high protein intake groups compared to the middle protein intake group (Fig. 3 ). Rapid eGFR decline was observed most commonly in the high protein intake group (62.5%, p < 0.05; Table 2 ). Binomial logistic analysis performed on risk factors for eGFR slope decline (adjusted for age at transplant and mean systolic blood pressure) found that low protein intake had a greater effect than middle protein intake on eGFR slope decline (OR = 3.12, 95%CI: 1.24–7.84; p < 0.05; Table 3 ); and that high protein intake had a significantly greater impact than middle protein intake on rapid eGFR slope decline (OR = 22.4, 95%CI: 3.21–157; p < 0.01; Table 3 ). Table 2 Clinical outcomes Low protein intake group (n = 41) Middle protein intake group (n = 41) High protein intake group (n = 8) P-value Mean eGFR slope at 1 year after transplantation (mL/min/1.73 m²) -0.89 (± 7.12) 2.44 (± 6.57) -3.56 (± 7.28) 0.01 eGFR at 1 year after transplantation (mL/min/1.73 m²) 39.0 (32.2–46.0) 39.0 (34.0-47.9) 36.6 (30.8–44.5) 0.8 BUN at 1 year after transplantation (mg/dL) 20.7 (15.8–24.8) 20.6 (17.0-24.9) 24.2 (21.7–27.2) 0.31 Alb at 1 year after transplantation (mg/dL) 4.30 (4.25–4.60) 4.50 (4.25–4.70) 4.30 (4.13–4.73) 0.35 Cr at 1 year after transplantation (mg/dL) 1.58 (1.21–1.79) 1.44 (1.24–1.79) 1.68 (1.05–1.86) 0.86 Rapid eGFR decline (%) 10 (24.4) 3 (7.3) 5 (62.5) 0.001 Abbreviations: eGFR estimated glomerular filtration rate, BUN blood urea nitrogen, Alb albumin, Cr creatinine Table 3 Impact of protein intake on eGFR slope eGFR slope decline Univariate Multivariate OR 95% CI P-value adjusted OR 95% CI P-value High protein intake group (n = 8) 3.21 0.67–15.5 0.14 3.22 0.65–15.9 0.15 Low protein intake group (n = 41) 3.01 1.22–7.41 0.02 3.12 1.24–7.84 0.02 Middle protein intake group (n = 41) ref ref Rapid eGFR decline (defined as a decrease > 5ml/min/1.73m²/year) Univariate Multivariate OR 95% CI P-value adjusted OR 95% CI P-value High protein intake group (n = 8) 21.1 3.31–135 0.001 22.4 3.21–157 0.002 Low protein intake group (n = 41) 4.09 1.03–16.2 0.04 4.04 1.00-16.4 0.05 Middle protein intake group (n = 41) ref ref Abbreviations: eGFR estimated glomerular filtration rate, ref reference, OR odds ratio, Cl confidence interval Discussion Diet management after kidney transplantation is crucial for maintaining kidney graft function but the effectiveness remains elusive, and there is currently no clear definition of optimal protein intake after kidney transplantation [ 12 ]. The major findings of the present evaluation of the effect of protein intake during the first year post-transplant on kidney function at 1 year are as follows. First, kidney graft function was maintained in the patient group that had middle protein intake (≥ 0.9 and < 1.2 g/kg IBW/day). Second, low protein intake in particular may result in decline in eGFR slope for kidney function compared to middle protein intake. Third, rapid eGFR decline was observed most often in the high protein intake group. To our knowledge, this study is the first to demonstrate the relationship between protein intake and kidney function in post kidney transplant patients in terms of eGFR slope. eGFR slope has been highlighted in recent years as a surrogate endpoint for CKD. Several studies have reported an association of greater eGFR slope decline with increased risk of developing end-stage kidney disease [ 10 ] [ 13 ]. Prior studies have reported that annual eGFR slope decline ranged from − 0.75 to − 1.06 mL/1.73 m²/year[ 14 , 15 ] in healthy adults in their 40s, was − 3.8 mL/min/year[ 16 ] in patients with an eGFR of 25–55 mL/min/1.73 m², and was − 1.88 and − 1.11 mL/min/1.73 m²/year in Japanese patients with CKD stage 3 and stage 4, respectively[ 17 ]. Clayton et al. showed that kidney function during the first year after transplantation was inversely correlated with later graft viability, and that the rate of change in eGFR during the first year exponentially increased the risk of transplant kidney dysfunction [ 9 ]. Therefore, this study aimed to determine the optimal protein intake after transplantation by evaluating change in eGFR slope. In conservative management of kidney failure, protein restriction is generally advocated to prevent glomerular hyperfiltration caused by a high-protein diet. However, excessive dietary restriction may lead to protein-energy wasting, which has been shown to accelerate the progression of kidney dysfunction and increase mortality. Therefore, an ideal protein intake of 0.8–1.0 g/kg IBW/day has been proposed for patients with Grade 3a CKD, and 0.6–0.8 g/kg IBW/day for those with Grade 3b CKD and higher [ 5 ]. The MDRD study primarily targeted patients with chronic kidney disease and did not specifically address kidney transplant recipients [ 18 ]. Nevertheless, the catabolic state associated with surgical stress, wound healing, and the use of corticosteroids after kidney transplantation cannot be ignored [ 19 ], and conventional protein intake may therefore result in insufficient protein consumption. Indeed, our study demonstrated that eGFR slope decline was greater in the low protein intake group than the middle protein intake group (–0.89 vs 2.44 mL/min/1.73m²/year). This result suggests that the combination of pre-transplant protein restriction and inadequate post-transplant protein intake may cause a further decline in kidney function. In contrast, high-protein diets exceeding 1.2 g/kg IBW/day in humans increased intraglomerular pressure due to the elimination of protein-derived nitrogen compounds [ 5 ], leading to hyperfiltration and a 1.32-fold increase in risk of eGFR reduction [ 20 ]. In experimental systems in mice, infusion of amino acids has been shown to cause an increase in kidney plasma flow and increase the glomerular filtration rate [ 21 ]. Cortinovis et al. have reported that a transplanted kidney functions as a single kidney, with reduced functional nephrons leading to “relative hyperfiltration”, and excessive protein intake resulting in “absolute hyperfiltration”; therefore, excessive protein load on a kidney transplant graft may not be recommended [ 22 ] [ 23 ]. In the present study, the greatest decline in eGFR slope was observed in the high protein intake group, and rapid eGFR decline was also common in this group. These results suggest that the high-protein diet may have caused “absolute hyperfiltration” that led to a rapid decline in kidney function. Rapid eGFR slope decline has been frequently reported in diabetic patients[ 24 ]. Nakahara et al. reported rapid eGFR decline in 32% of patients with diabetic kidney disease[ 24 ]. In the present study, a total of 18 patients had rapid eGFR decline, accounting for approximately 20% of all participants. Notably, similar to diabetic patients, rapid eGFR slope decline was observed following kidney transplantation. In particular, rapid eGFR slope decline occurred in 62.5% of the high protein intake group. The importance of nutritional guidance after transplantation is underscored by the fact that rapid eGFR decline was limited to 7.3% in the middle protein intake group (Table 2 ). In addition, the proportion of patients with high protein intake was only 8.9%. At our center, our dietitians provide nutritional guidance after every outpatient visit within 3 months after transplantation. In addition to assessing nutritional status, nutritional management also requires attention to oral medication adherence, nutrition knowledge, the patient’s beliefs about nutrition, and their cognitive function[ 12 ]. Moreover, outpatient 24-hour urine collection is easily incorporated into dietary planning at the next outpatient visit, as the results can be explained on the same day. Kidney transplant patients are educated to submit a urine storage test each time they have an outpatient visit at our hospital. These detailed considerations might have contributed to reducing the number of the present participants with high protein intake. There are several limitations to this study. This is a single-center study, and a larger number of cases need to be accumulated. The low number of participants in the high protein intake group can be attributed to the frequent provision of nutritional guidance interventions at our institution within the first year, which gave patients more opportunities to be mindful of avoiding excessive protein intake. Additionally, the substantial number of participants in the low protein intake group could be due to the continuation of dietary habits from the pre-dialysis stage of chronic kidney disease, where adherence to protein restriction was emphasized. This study did not examine the long-term prognosis of kidney function. A larger longitudinal study is needed to further validate our findings. Conclusions The results of this study suggest that both low and high protein intake during the first year post-transplant may negatively impact kidney function at 1 year. Our findings indicate that evaluating protein intake during the first year post-transplant could help maintain better control of eGFR at the 1-year mark. Evidence regarding protein intake after kidney transplantation is extremely limited. Therefore, the results of this study will contribute to determining the appropriate protein intake for post-transplant patients. Abbreviations IBW ideal body weight eGFR estimated glomerular filtration rate CKD chronic kidney disease BUN blood urea nitrogen LDL low-density lipoprotein HbA1c hemoglobin A1c CRP C-reactive protein ARB angiotensin II receptor blocker TAC tacrolimus CsA cyclosporine MMF mycophenolate mofetil EVR everolimus ORs odds ratios Cis confidence intervals DM diabetes mellitus Declarations Ethical approval and consent to participate All procedures were performed in accordance with the ethical standards of our institution and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. Consent for publication The institutional review board of Kitasato University Hospital waived the need to obtain informed consent from the patients because of the retrospective study design. Availability of data and materials Data sharing is not applicable to this article as no datasets were generated or analysed during the current study. Competing Interests All of the authors declare no competing interests. Funding The authors did not receive support from any organization for the submitted work. Author Contributions AT1, AT2, MY, YT, IY, NF, KK, ID, YK, and TY treated the patient. AT1, AT2, MK drafted the manuscript. AT1, AT2, MK, and TY discussed the case. AT2, MK and TY revised the manuscript critically. All authors approved the final version of the manuscript. Acknowledgments The authors sincerely thank all study participants and the personnel at Kitasato university hospital who were involved in data collection. 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Imaizumi T, Komaba H, Hamano T, Nangaku M, Murotani K, Hasegawa T, et al. Clinically meaningful eGFR slope as a surrogate endpoint differs across CKD stages and slope evaluation periods: the CKD-JAC study. Clin Kidney J. 2025;18(2):sfae398. doi: 10.1093/ckj/sfae398 . Menon V, Kopple JD, Wang X, Beck GJ, Collins AJ, Kusek JW, et al. Effect of a very low-protein diet on outcomes: long-term follow-up of the Modification of Diet in Renal Disease (MDRD) Study. Am J Kidney Dis. 2009;53(2):208–17. doi: 10.1053/j.ajkd.2008.08.009 . Narasaki Y, Rhee CM, Kalantar-Zadeh K, Rastegar M. Why protein-energy wasting leads to faster progression of chronic kidney disease. Curr Opin Nephrol Hypertens. 2025;34(1):55–66. doi: 10.1097/mnh.0000000000001035 . Jhee JH, Kee YK, Park S, Kim H, Park JT, Han SH, et al. High-protein diet with renal hyperfiltration is associated with rapid decline rate of renal function: a community-based prospective cohort study. Nephrol Dial Transplant. 2020;35(1):98–106. doi: 10.1093/ndt/gfz115 . King AJ, Troy JL, Anderson S, Neuringer JR, Gunning M, Brenner BM. Nitric oxide: a potential mediator of amino acid-induced renal hyperemia and hyperfiltration. Journal of the American Society of Nephrology. 1991;1(12):1271–7. doi: 10.1681/asn.V1121271 . Brenner BM, Cohen RA, Milford EL. In renal transplantation, one size may not fit all. Journal of the American Society of Nephrology. 1992;3(2):162–9. doi: 10.1681/asn.V32162 . Cortinovis M, Perico N, Ruggenenti P, Remuzzi A, Remuzzi G. Glomerular hyperfiltration. Nat Rev Nephrol. 2022;18(7):435–51. doi: 10.1038/s41581-022-00559-y . Nakahara E, Waki K, Kurasawa H, Mimura I, Seki T, Fujino A, et al. Predicting rapid decline in kidney function among type 2 diabetes patients: A machine learning approach. Heliyon. 2025;11(1):e40566. doi: 10.1016/j.heliyon.2024.e40566 . Additional Declarations No competing interests reported. Supplementary Files Supplementaryfig1.tiff Supplementary figure 1: Protein intake (g/day) in the year after kidney transplantation. Supplementaryfig2.tiff Supplementary figure 2: Protein intake (g/kg IBW) in the year after kidney transplantation. IBW: ideal body weight. RRTSupplementarytable2025.7.17.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7148397","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":488811583,"identity":"f85148bb-0f29-4a4d-94d7-fd51275ebcdc","order_by":0,"name":"Tetsuya Abe","email":"data:image/png;base64,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","orcid":"","institution":"Kitasato University School of Medicine","correspondingAuthor":true,"prefix":"","firstName":"Tetsuya","middleName":"","lastName":"Abe","suffix":""},{"id":488811584,"identity":"0ac3b415-8803-48e6-82d2-95e0abb662d8","order_by":1,"name":"Togo Aoyama","email":"","orcid":"","institution":"Kitasato University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Togo","middleName":"","lastName":"Aoyama","suffix":""},{"id":488811586,"identity":"c644fa1c-165e-432b-9bef-cf870e8c7396","order_by":2,"name":"Keiichi Matsuzaki","email":"","orcid":"","institution":"Kitasato University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Keiichi","middleName":"","lastName":"Matsuzaki","suffix":""},{"id":488811588,"identity":"3cd03c93-9b54-464d-b5d2-b001cae3e849","order_by":3,"name":"Yuko Morioka","email":"","orcid":"","institution":"Kitasato University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Yuko","middleName":"","lastName":"Morioka","suffix":""},{"id":488811590,"identity":"63806b0e-b6ea-4b2c-8d84-745ee3b1c90c","order_by":4,"name":"Tomoko Yoshida","email":"","orcid":"","institution":"Kitasato University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Tomoko","middleName":"","lastName":"Yoshida","suffix":""},{"id":488811594,"identity":"bc2a9922-f518-4a7b-ae5f-baa3c97fe3f8","order_by":5,"name":"Yuki Imura","email":"","orcid":"","institution":"Kitasato University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Yuki","middleName":"","lastName":"Imura","suffix":""},{"id":488811600,"identity":"5bff8e62-a083-465a-bad0-e0a2f9d338a7","order_by":6,"name":"Fumino Noguchi","email":"","orcid":"","institution":"Kitasato University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Fumino","middleName":"","lastName":"Noguchi","suffix":""},{"id":488811601,"identity":"a22a0263-9c5a-4f8e-b743-664d3d667077","order_by":7,"name":"Kazuki Kitajima","email":"","orcid":"","institution":"Kitasato University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Kazuki","middleName":"","lastName":"Kitajima","suffix":""},{"id":488811604,"identity":"66330c55-e868-4d1d-9fe7-33f3867f1a75","order_by":8,"name":"Daisuke Ishii","email":"","orcid":"","institution":"Kitasato University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Daisuke","middleName":"","lastName":"Ishii","suffix":""},{"id":488811607,"identity":"2870c323-bc14-4e83-89b6-b02107d15231","order_by":9,"name":"Kazunari Yoshida","email":"","orcid":"","institution":"Kitasato University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Kazunari","middleName":"","lastName":"Yoshida","suffix":""},{"id":488811611,"identity":"f22c53d6-a928-4ac9-924c-bfb0a03f626a","order_by":10,"name":"Yasuo Takeuchi","email":"","orcid":"","institution":"Kitasato University School of Medicine","correspondingAuthor":false,"prefix":"","firstName":"Yasuo","middleName":"","lastName":"Takeuchi","suffix":""}],"badges":[],"createdAt":"2025-07-17 11:08:24","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7148397/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7148397/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":87664629,"identity":"98399f85-f083-4d8b-b389-cfbd95a1fcc5","added_by":"auto","created_at":"2025-07-27 10:59:41","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":106773,"visible":true,"origin":"","legend":"\u003cp\u003eFlow chart of the study population. After applying the exclusion criteria, a total of 90 kidney transplant patients were enrolled in the study.\u003c/p\u003e","description":"","filename":"OnlineFig1.png","url":"https://assets-eu.researchsquare.com/files/rs-7148397/v1/f98bea65679c189a8c7dfc67.png"},{"id":87664631,"identity":"09ea6750-91a3-48bf-bc1a-a84bfb25084e","added_by":"auto","created_at":"2025-07-27 10:59:41","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":113440,"visible":true,"origin":"","legend":"\u003cp\u003eChange in eGFR at each time point after kidney transplantation. There were no significant differences among the three groups at baseline.\u003c/p\u003e\n\u003cp\u003eeGFR: estimated glomerular filtration rate.\u003c/p\u003e","description":"","filename":"OnlineFig2.png","url":"https://assets-eu.researchsquare.com/files/rs-7148397/v1/98b8e12b532e4849946cd2c3.png"},{"id":87664639,"identity":"43305b0a-9924-4b0f-9a0d-c3a6b68c044f","added_by":"auto","created_at":"2025-07-27 10:59:41","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":26613,"visible":true,"origin":"","legend":"\u003cp\u003eeGFR slopes at 1 year after kidney transplantation for each protein intake group. eGFR slope decline was greater in low and high protein intake groups than in the middle protein intake group.\u003c/p\u003e\n\u003cp\u003eeGFR: estimated glomerular filtration rate.\u003c/p\u003e","description":"","filename":"OnlineFig3.png","url":"https://assets-eu.researchsquare.com/files/rs-7148397/v1/b635c4d0c581d70d8d48cd36.png"},{"id":89958510,"identity":"6c01ae9b-5118-446d-a3d9-27f564fbb719","added_by":"auto","created_at":"2025-08-27 00:16:24","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1332208,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7148397/v1/38f390c6-3a34-48e9-930c-295df620a91e.pdf"},{"id":87665638,"identity":"704f6bfe-6a6a-445d-ba1c-f3fda0b2c4b1","added_by":"auto","created_at":"2025-07-27 11:07:41","extension":"tiff","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":123982,"visible":true,"origin":"","legend":"\u003cp\u003eSupplementary figure 1: Protein intake (g/day) in the year after kidney transplantation.\u003c/p\u003e","description":"","filename":"Supplementaryfig1.tiff","url":"https://assets-eu.researchsquare.com/files/rs-7148397/v1/446e49030af37f6d65b1d70f.tiff"},{"id":87664634,"identity":"d8a52b80-8f94-4ccf-828b-fe3507f56df8","added_by":"auto","created_at":"2025-07-27 10:59:41","extension":"tiff","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":126416,"visible":true,"origin":"","legend":"\u003cp\u003eSupplementary figure 2: Protein intake (g/kg IBW) in the year after kidney transplantation.\u003c/p\u003e\n\u003cp\u003eIBW: ideal body weight.\u003c/p\u003e","description":"","filename":"Supplementaryfig2.tiff","url":"https://assets-eu.researchsquare.com/files/rs-7148397/v1/ffe38f85bc39858de96b8a80.tiff"},{"id":87664643,"identity":"d99dea81-8715-4c84-a0a7-9b81f66c9641","added_by":"auto","created_at":"2025-07-27 10:59:41","extension":"docx","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":33218,"visible":true,"origin":"","legend":"","description":"","filename":"RRTSupplementarytable2025.7.17.docx","url":"https://assets-eu.researchsquare.com/files/rs-7148397/v1/2c063c8e777750b0437e904c.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Impact of Protein Intake on eGFR Slope One Year Post Kidney Transplantation: A Single- center Retrospective Study","fulltext":[{"header":"Background","content":"\u003cp\u003eKidney transplantation is widely recognized as the best treatment for patients with end-stage kidney failure. In Japan, approximately 90% of kidney transplants are performed using organs from living donors, with the remainder from deceased donors. The waiting period is approximately 15 years for a deceased kidney transplant, underscoring the serious shortage of available donors. Therefore, it is desirable that recipients maintain optimal kidney function following transplantation. As the number of kidney transplant patients in Japan continues to increase annually, comprehensive management aimed at preventing rejection and infection that also addresses nutritional care is crucial for maintaining optimal kidney function thereafter. In addition, regular nutritional guidance from dietitians has been shown to mitigate decline in post-transplant estimated glomerular filtration rate (eGFR)[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. It is well established that protein restriction is essential for patients with chronic kidney disease (CKD). However, excessive protein restriction can lead to chronic inflammation, oxidative stress, and muscle weakness, potentially worsening both kidney function and overall prognosis[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]. In contrast, excessive protein intake has been shown to cause hyperfiltration, in both human and animal experiments[\u003cspan additionalcitationids=\"CR5 CR6\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e–\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Post-transplant kidney function improves dramatically, often approaching Grade 3b. Nevertheless, the optimal level of protein restriction after kidney transplantation has not yet been established, and its effectiveness remains unclear. Clayton et al. reported that the rate of change in eGFR in the first year after kidney transplantation is a predictor of patient survival and graft survival[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], and eGFR slope has recently been suggested as a surrogate endpoint for predicting kidney prognosis [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Therefore, it is important to investigate the risk factors associated with kidney dysfunction in the first year after kidney transplantation. We hypothesized that both excessive protein restriction and high protein intake after kidney transplantation would adversely affect graft kidney function, similar to those observed in CKD. The purpose of this study was to evaluate the effect of protein intake during the first year after kidney transplantation on kidney function at 1 year.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003e\u003cb\u003eStudy Design\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThis study included 150 kidney transplant patients aged ≥ 18 years who underwent kidney transplantation at Kitasato university hospital between 1 January 2009 and 1 February 2020. The exclusion criteria were age \u0026lt; 18 years, loss to follow-up within 1 year after kidney transplantation, rejection within 1 year after kidney transplantation, and patients who received a deceased donor kidney transplant. After excluding 60 patients, a final total of 90 patients were retrospectively observed (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). This clinical study was approved by the Ethics Committee (approval No. B24-175). The study was conducted in accordance with the Declaration of Helsinki and adhered to the principles of the Declaration of Istanbul as outlined in the Declaration of Istanbul on Organ Trafficking and Transplant Tourism.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eMeasurements\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe clinical features and laboratory results of recipients during hospitalization for kidney transplant surgery were used as the baseline values. Clinical characteristics included age at transplantation, sex, BMI at discharge, preemptive kidney transplantation rate, primary disease leading to kidney failure, types and concentrations of immunosuppressive medications, percentage of rituximab use, duration of dialysis, percentage of blood-type-matched or incompatible transplants, number of HLA mismatches, and mean systolic and diastolic blood pressures. Donor kidney weight, warm ischemic time, cold ischemic time, and total ischemic time were also evaluated. Mean blood pressure was calculated from blood pressure measurements taken during outpatient visits at 1, 3, 6, 9, and 12 months after kidney transplantation.\u003c/p\u003e\u003cp\u003eThe following blood test results were evaluated: hemoglobin, hematocrit, serum albumin, serum creatinine, eGFR, blood urea nitrogen (BUN), low-density lipoprotein (LDL), hemoglobin A1c (HbA1c), C-reactive protein (CRP). Results from Day 21 after surgery were used for evaluation of serum creatinine and eGFR. For LDL, HbA1c, and CRP, the results during hospitalization for kidney transplantation were used. The use of angiotensin II receptor blocker (ARB) within 1 year was also evaluated.\u003c/p\u003e\u003cp\u003e\u003cb\u003eImmunosuppression\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe standard maintenance immunosuppressants used were steroids, calcineurin inhibitors (tacrolimus [TAC] or cyclosporine [CsA])), and metabolic antagonists (mycophenolate mofetil [MMF] and/or everolimus [EVR] and/or mizoribine). In all cases, a steroid (methylprednisolone, 250 mg intravenously) was administered prior to surgery, intraoperatively, and on the day following surgery. Basiliximab was also administered in all cases. The target levels of immunosuppressive drugs used at our hospital during the study period were as follows. The TAC extended-release target trough level was 7–8 ng/mL, after which the maintenance dose was reduced to achieve 5–6 ng/mL. Mycophenolate mofetil was adjusted to achieve a target area under the concentration–time curve of 40–80 µg·h/mL during the first 4 hours after administration. The target C2 level for CsA was 800–1000 ng/mL for the first 3 months, after which the maintenance dose was reduced to achieve 600–800 ng/mL. EVR was adjusted to achieve a trough level of 3–5 ng/mL. Prednisolone was started at a dose of 30 mg/day and subsequently reduced to 5 mg/day at 3 weeks after kidney transplantation.\u003c/p\u003e\u003cp\u003e\u003cb\u003eDefinitions for grouping and study outcomes\u003c/b\u003e\u003c/p\u003e\u003cp\u003eProtein intake in the year following transplantation was estimated from 24-hour urine collection using Maroni’s formula. Protein intake was calculated as the mean daily protein intake from 24-hour urine collection at 3, 6, 9, and 12 months after transplantation. Patients with an average daily protein intake of \u0026lt; 0.9 g/kg IBW/day were assigned to the low protein intake group, those with ≥ 0.9 and \u0026lt; 1.2 g/kg IBW/day were assigned to the middle protein intake group, and those with ≥ 1.2 g/kg IBW/day were assigned to the high protein intake group (Supplementary table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, Supplementary Figs.\u0026nbsp;1, 2).\u003c/p\u003e\u003cp\u003eThe primary outcome was eGFR slope in the first year after transplantation. eGFR slope was calculated by plotting the eGFR measurements at each time point during the first year after transplantation, deriving a linear approximation equation, and using the slope of the resulting line to represent the annual rate of change. The secondary outcome was the incidence of rapid eGFR decline, defined as a decrease of \u0026gt; 5 mL/min/1.73 m\u003csup\u003e2\u003c/sup\u003e/year [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e].\u003c/p\u003e\u003ch2\u003eStatistical Analysis\u003c/h2\u003e\u003cp\u003eData for normally distributed continuous variables are presented as mean ± standard deviation, and data for non-normally distributed continuous variables are presented as median (interquartile range). The χ\u003csup\u003e2\u003c/sup\u003e test, one-way ANOVA, and Kruskal–Wallis test were used for comparisons among the three groups. Dunnett’s test was used for multiple comparisons. Binomial logistic analysis was performed to evaluate predictors of the eGFR slope at 1 year after kidney transplantation and predictors of eGFR slope decline, and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated.\u003c/p\u003e\u003cp\u003eAll statistical analyses were performed using GraphPad Prism version 10.2.0 for Windows (GraphPad Software, Boston, MA; \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ewww.graphpad.com\u003c/a\u003e\u003c/span\u003e\u003cspan address=\"http://www.graphpad.com\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e). All tests were two-sided, and p \u0026lt; 0.05 was considered statistically significant. All CIs were calculated at the 95% confidence level.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cb\u003ePatient characteristics\u003c/b\u003e\u003c/p\u003e\u003cp\u003eOf the 150 patients admitted to the study, 90 were followed up for 1 year after transplantation (41, 41, and 8 in the middle, low, and high protein intake groups, respectively). There were no differences among the groups in terms of age at the time of kidney transplantation, sex, duration of dialysis, or use of ARB. The rate of diabetes mellitus (DM) as the primary disease was highest in the high protein intake group and lowest in the low protein intake group. BMI was significantly the lowest in the low protein intake group. Mean systolic blood pressure was highest in the high protein intake group. There was no significant difference in diastolic blood pressure among the groups. Regarding donor factors, there were no differences in kidney weight or ischemic time among the groups. There was no difference in trough TAC level at 6 months after transplantation among the groups (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). There was no significant difference in median eGFR at 21 days after transplantation among the groups (44.0 [32.2\u0026ndash;47.3] in the low protein intake group versus 39.0 [29.0\u0026ndash;44.8] in the middle protein intake group versus 37.1 [28.0\u0026ndash;56.6] in the low protein intake group; p\u0026thinsp;=\u0026thinsp;0.33; Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). There were no significant differences in Hb, LDL, HbA1c, or CRP among the groups (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003ePatient characteristics\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLow protein intake group (n\u0026thinsp;=\u0026thinsp;41)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMiddle protein intake group (n\u0026thinsp;=\u0026thinsp;41)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eHigh protein intake group (n\u0026thinsp;=\u0026thinsp;8)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eCharacteristic\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge at transplantation (years)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e43.2 (\u0026plusmn;\u0026thinsp;15.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e45.8 (\u0026plusmn;\u0026thinsp;14.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e48.1 (\u0026plusmn;\u0026thinsp;13.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.58\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMale sex (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e25 (61)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e28 (68.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5 (62.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.78\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePEKT (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e5 (12.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9 (22.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0 (0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.21\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBMI (kg/m\u0026sup2;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e18.9 (16.8\u0026ndash;20.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e21.4 (19.4\u0026ndash;22.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e21.0 (18.7\u0026ndash;28.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.003\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDialysis period (months)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e20 (3.5\u0026ndash;90)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10 (1.0-34.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e29 (7.5\u0026ndash;53.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBlood-group-compatible transplant (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e31 (75.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e31 (75.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e7 (87.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.75\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHLA mismatch\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3.0 (2.5-4.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3.0 (2.0-4.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3.5 (3.0-4.75)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.38\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eKidney weight (g)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e180 (170-223.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e175 (147.8\u0026ndash;200)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e187.5 (181.3-233.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.07\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWIT (min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e5.0 (4.0\u0026ndash;6.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5.0 (4.0\u0026ndash;6.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4.5 (3.25-5.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.22\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCIT (min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e72.0 (58.0\u0026ndash;96.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e70.0 (63.0-90.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e57.5 (42.5\u0026ndash;74.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTIT (min)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e76.0 (63.5-101.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e77.0 (67.3\u0026ndash;96.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e62.0 (46.8\u0026ndash;78.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.07\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMean systolic blood pressure (mmHg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e121.6 (111.7-130.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e126.0 (119.6-130.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e131.7 (124.4-137.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.04\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMean diastolic blood pressure (mmHg)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e75.0 (70.6\u0026ndash;80.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e77.6 (71.3\u0026ndash;82.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e76.9 (71.5\u0026ndash;81.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.54\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHemoglobin (g/dL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10.4 (9.2\u0026ndash;11.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10.2 (8.95\u0026ndash;11.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e9.95 (8.78-11.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.57\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHematocrit (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e32.1 (28.8\u0026ndash;35.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e31.6 (29.5\u0026ndash;35.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e29.9 (26.4\u0026ndash;33.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.39\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSerum albumin (g/dL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3.9 (3.7\u0026ndash;4.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3.9 (3.75\u0026ndash;4.25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3.85 (3.55\u0026ndash;4.30)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.83\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSerum creatinine (mg/dL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.47 (1.12\u0026ndash;1.68)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.46 (1.28\u0026ndash;1.96)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.47 (1.03\u0026ndash;2.13)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.68\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eeGFR (mL/min/1.73 m\u0026sup2;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e44.0 (32.2\u0026ndash;47.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e39.0 (29.0-44.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e37.1 (28.0-56.6)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.33\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBUN (mg/dL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e17.1 (12.7\u0026ndash;20.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e18.9 (15.0-21.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e17.3 (10.3\u0026ndash;21.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.43\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLDL (mg/dL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e107 (87\u0026ndash;118)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e93 (81-113.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e87.5 (74.3\u0026ndash;102)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.19\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHbA1c (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e5.4 (5.2\u0026ndash;5.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5.6 (5.1\u0026ndash;6.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5.6 (5.1\u0026ndash;6.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.72\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCRP (mg/dL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.07 (0.03\u0026ndash;0.45)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.07 (0.03\u0026ndash;0.15)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.03 (0.03\u0026ndash;0.16)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.33\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eUse of ARB within 1 year\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e17 (41.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e16 (39.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1 (12.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.3\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eDiagnosis\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eDM (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2 (4.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e7 (17.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3 (37.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.03\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCGN (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e23 (56.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e21 (51.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3 (37.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.62\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eADPKD (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1 (2.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2 (4.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1 (12.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.44\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eRenal sclerosis (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3 (7.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1 (2.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0 (0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.46\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOther (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e12 (29.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10 (24.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1 (12.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.59\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003eImmunosuppression\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTAC/CsA (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e37 (90.2)/ 4 (9.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e41 (100)/ 0 (0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e7 (87.5)/ 1 (12.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.1\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMMF (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e38 (92.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e38 (92.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e7 (87.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.87\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eEVR (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e11 (26.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e8 (19.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3 (37.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMZB (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3 (7.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1 (2.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1 (12.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.42\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eRituximab (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e14 (34.1)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e13 (31.7)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1 (12.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.48\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMMF dose at 6 months\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1000 (1000\u0026ndash;1000)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1000 (937.5\u0026ndash;1000)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1000 (500\u0026ndash;1000)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.89\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eConcentration level\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTAC trough (ng/mL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4.80 (3.90\u0026ndash;6.50)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.80 (3.70\u0026ndash;6.05)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e3.60 (2.30\u0026ndash;4.70)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.23\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCsA C2 level (ng/mL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e255 (115.0-257.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e151.0 (151.0-151.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e-\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003eAbbreviations: PEKT preemptive kidney transplantation, BMI body mass index, HLA human leukocyte antigen, WIT warm ischemic time, CIT cold ischemic time, TIT total ischemic time, eGFR estimated glomerular filtration rate, BUN blood urea nitrogen, LDL low-density lipoprotein, HbA1c hemoglobin A1c, CRP c-reactive protein, ARB angiotensin receptor blocker, DM diabetes mellitus, CGN chronic glomerular nephritis, ADPKD autosomal dominant polycystic kidney disease, TAC tacrolimus, CsA cyclosporine, MMF mycophenolate mofetil, EVR everolimus, MZB mizoribine\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cb\u003eOutcomes\u003c/b\u003e\u003c/p\u003e\u003cp\u003eMean eGFR slope (mL/min/1.73 m\u003csup\u003e2\u003c/sup\u003e/year) at 1 year after living donor kidney transplantation was \u0026minus;\u0026thinsp;0.89 (\u0026plusmn;\u0026thinsp;7.12) in the low protein intake group, 2.44 (\u0026plusmn;\u0026thinsp;6.57) in the middle protein intake group, and \u0026minus;\u0026thinsp;3.56 (\u0026plusmn;\u0026thinsp;7.28) in the high protein intake group. Mean eGFR slope did not decline in the middle protein intake group but declined in both the low and high protein intake groups (p\u0026thinsp;\u0026lt;\u0026thinsp;0.05; Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Dunnett\u0026rsquo;s test for multiple comparisons found a significant difference in eGFR slope decline in both the low and high protein intake groups compared to the middle protein intake group (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e). Rapid eGFR decline was observed most commonly in the high protein intake group (62.5%, p\u0026thinsp;\u0026lt;\u0026thinsp;0.05; Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). Binomial logistic analysis performed on risk factors for eGFR slope decline (adjusted for age at transplant and mean systolic blood pressure) found that low protein intake had a greater effect than middle protein intake on eGFR slope decline (OR\u0026thinsp;=\u0026thinsp;3.12, 95%CI: 1.24\u0026ndash;7.84; p\u0026thinsp;\u0026lt;\u0026thinsp;0.05; Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e); and that high protein intake had a significantly greater impact than middle protein intake on rapid eGFR slope decline (OR\u0026thinsp;=\u0026thinsp;22.4, 95%CI: 3.21\u0026ndash;157; p\u0026thinsp;\u0026lt;\u0026thinsp;0.01; Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eClinical outcomes\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eLow protein intake group (n\u0026thinsp;=\u0026thinsp;41)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMiddle protein intake group\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;41)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eHigh protein intake group (n\u0026thinsp;=\u0026thinsp;8)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eP-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMean eGFR slope at 1 year after transplantation (mL/min/1.73 m\u0026sup2;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e-0.89 (\u0026plusmn;\u0026thinsp;7.12)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2.44 (\u0026plusmn;\u0026thinsp;6.57)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e-3.56 (\u0026plusmn;\u0026thinsp;7.28)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.01\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eeGFR at 1 year after transplantation (mL/min/1.73 m\u0026sup2;)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e39.0 (32.2\u0026ndash;46.0)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e39.0 (34.0-47.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e36.6 (30.8\u0026ndash;44.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.8\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eBUN at 1 year after transplantation (mg/dL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e20.7 (15.8\u0026ndash;24.8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e20.6 (17.0-24.9)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e24.2 (21.7\u0026ndash;27.2)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.31\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAlb at 1 year after transplantation (mg/dL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4.30 (4.25\u0026ndash;4.60)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.50 (4.25\u0026ndash;4.70)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e4.30 (4.13\u0026ndash;4.73)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.35\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCr at 1 year after transplantation (mg/dL)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.58 (1.21\u0026ndash;1.79)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.44 (1.24\u0026ndash;1.79)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.68 (1.05\u0026ndash;1.86)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.86\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eRapid eGFR decline (%)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10 (24.4)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3 (7.3)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e5 (62.5)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e0.001\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"5\"\u003eAbbreviations: eGFR estimated glomerular filtration rate, BUN blood urea nitrogen, Alb albumin, Cr creatinine\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eImpact of protein intake on eGFR slope\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"8\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"7\" nameend=\"c8\" namest=\"c2\"\u003e\u003cp\u003eeGFR slope decline\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e\u003cp\u003eUnivariate\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colspan=\"3\" nameend=\"c8\" namest=\"c6\"\u003e\u003cp\u003eMultivariate\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eOR\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e95% CI\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eP-value\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eadjusted OR\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003e95% CI\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eP-value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHigh protein intake group (n\u0026thinsp;=\u0026thinsp;8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3.21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.67\u0026ndash;15.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3.22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.65\u0026ndash;15.9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.15\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLow protein intake group (n\u0026thinsp;=\u0026thinsp;41)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3.01\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.22\u0026ndash;7.41\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.02\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3.12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e1.24\u0026ndash;7.84\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.02\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMiddle protein intake group (n\u0026thinsp;=\u0026thinsp;41)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e\u003cp\u003eref\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c8\" namest=\"c6\"\u003e\u003cp\u003eref\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\" morerows=\"2\" rowspan=\"3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"7\" nameend=\"c8\" namest=\"c2\"\u003e\u003cp\u003eRapid eGFR decline (defined as a decrease\u0026thinsp;\u0026gt;\u0026thinsp;5ml/min/1.73m\u0026sup2;/year)\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e\u003cp\u003eUnivariate\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c8\" namest=\"c6\"\u003e\u003cp\u003eMultivariate\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eOR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e95% CI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eP-value\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003eadjusted OR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e95% CI\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003eP-value\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHigh protein intake group (n\u0026thinsp;=\u0026thinsp;8)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e21.1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e3.31\u0026ndash;135\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.001\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e22.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e3.21\u0026ndash;157\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.002\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLow protein intake group (n\u0026thinsp;=\u0026thinsp;41)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4.09\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e1.03\u0026ndash;16.2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e0.04\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e4.04\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e1.00-16.4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.05\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMiddle protein intake group (n\u0026thinsp;=\u0026thinsp;41)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e\u003cp\u003eref\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c8\" namest=\"c6\"\u003e\u003cp\u003eref\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"8\"\u003eAbbreviations: eGFR estimated glomerular filtration rate, ref reference, OR odds ratio, Cl confidence interval\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eDiet management after kidney transplantation is crucial for maintaining kidney graft function but the effectiveness remains elusive, and there is currently no clear definition of optimal protein intake after kidney transplantation [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The major findings of the present evaluation of the effect of protein intake during the first year post-transplant on kidney function at 1 year are as follows. First, kidney graft function was maintained in the patient group that had middle protein intake (\u0026ge;\u0026thinsp;0.9 and \u0026lt;\u0026thinsp;1.2 g/kg IBW/day). Second, low protein intake in particular may result in decline in eGFR slope for kidney function compared to middle protein intake. Third, rapid eGFR decline was observed most often in the high protein intake group. To our knowledge, this study is the first to demonstrate the relationship between protein intake and kidney function in post kidney transplant patients in terms of eGFR slope.\u003c/p\u003e\u003cp\u003eeGFR slope has been highlighted in recent years as a surrogate endpoint for CKD. Several studies have reported an association of greater eGFR slope decline with increased risk of developing end-stage kidney disease [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Prior studies have reported that annual eGFR slope decline ranged from \u0026minus;\u0026thinsp;0.75 to \u0026minus;\u0026thinsp;1.06 mL/1.73 m\u0026sup2;/year[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] in healthy adults in their 40s, was \u0026minus;\u0026thinsp;3.8 mL/min/year[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] in patients with an eGFR of 25\u0026ndash;55 mL/min/1.73 m\u0026sup2;, and was \u0026minus;\u0026thinsp;1.88 and \u0026minus;\u0026thinsp;1.11 mL/min/1.73 m\u0026sup2;/year in Japanese patients with CKD stage 3 and stage 4, respectively[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Clayton et al. showed that kidney function during the first year after transplantation was inversely correlated with later graft viability, and that the rate of change in eGFR during the first year exponentially increased the risk of transplant kidney dysfunction [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Therefore, this study aimed to determine the optimal protein intake after transplantation by evaluating change in eGFR slope.\u003c/p\u003e\u003cp\u003eIn conservative management of kidney failure, protein restriction is generally advocated to prevent glomerular hyperfiltration caused by a high-protein diet. However, excessive dietary restriction may lead to protein-energy wasting, which has been shown to accelerate the progression of kidney dysfunction and increase mortality. Therefore, an ideal protein intake of 0.8\u0026ndash;1.0 g/kg IBW/day has been proposed for patients with Grade 3a CKD, and 0.6\u0026ndash;0.8 g/kg IBW/day for those with Grade 3b CKD and higher [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. The MDRD study primarily targeted patients with chronic kidney disease and did not specifically address kidney transplant recipients [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Nevertheless, the catabolic state associated with surgical stress, wound healing, and the use of corticosteroids after kidney transplantation cannot be ignored [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], and conventional protein intake may therefore result in insufficient protein consumption. Indeed, our study demonstrated that eGFR slope decline was greater in the low protein intake group than the middle protein intake group (\u0026ndash;0.89 vs 2.44 mL/min/1.73m\u0026sup2;/year). This result suggests that the combination of pre-transplant protein restriction and inadequate post-transplant protein intake may cause a further decline in kidney function.\u003c/p\u003e\u003cp\u003eIn contrast, high-protein diets exceeding 1.2 g/kg IBW/day in humans increased intraglomerular pressure due to the elimination of protein-derived nitrogen compounds [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e], leading to hyperfiltration and a 1.32-fold increase in risk of eGFR reduction [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. In experimental systems in mice, infusion of amino acids has been shown to cause an increase in kidney plasma flow and increase the glomerular filtration rate [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Cortinovis et al. have reported that a transplanted kidney functions as a single kidney, with reduced functional nephrons leading to \u0026ldquo;relative hyperfiltration\u0026rdquo;, and excessive protein intake resulting in \u0026ldquo;absolute hyperfiltration\u0026rdquo;; therefore, excessive protein load on a kidney transplant graft may not be recommended [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e] [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. In the present study, the greatest decline in eGFR slope was observed in the high protein intake group, and rapid eGFR decline was also common in this group. These results suggest that the high-protein diet may have caused \u0026ldquo;absolute hyperfiltration\u0026rdquo; that led to a rapid decline in kidney function.\u003c/p\u003e\u003cp\u003eRapid eGFR slope decline has been frequently reported in diabetic patients[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Nakahara et al. reported rapid eGFR decline in 32% of patients with diabetic kidney disease[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. In the present study, a total of 18 patients had rapid eGFR decline, accounting for approximately 20% of all participants. Notably, similar to diabetic patients, rapid eGFR slope decline was observed following kidney transplantation. In particular, rapid eGFR slope decline occurred in 62.5% of the high protein intake group. The importance of nutritional guidance after transplantation is underscored by the fact that rapid eGFR decline was limited to 7.3% in the middle protein intake group (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). In addition, the proportion of patients with high protein intake was only 8.9%. At our center, our dietitians provide nutritional guidance after every outpatient visit within 3 months after transplantation. In addition to assessing nutritional status, nutritional management also requires attention to oral medication adherence, nutrition knowledge, the patient\u0026rsquo;s beliefs about nutrition, and their cognitive function[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Moreover, outpatient 24-hour urine collection is easily incorporated into dietary planning at the next outpatient visit, as the results can be explained on the same day. Kidney transplant patients are educated to submit a urine storage test each time they have an outpatient visit at our hospital. These detailed considerations might have contributed to reducing the number of the present participants with high protein intake.\u003c/p\u003e\u003cp\u003eThere are several limitations to this study. This is a single-center study, and a larger number of cases need to be accumulated. The low number of participants in the high protein intake group can be attributed to the frequent provision of nutritional guidance interventions at our institution within the first year, which gave patients more opportunities to be mindful of avoiding excessive protein intake. Additionally, the substantial number of participants in the low protein intake group could be due to the continuation of dietary habits from the pre-dialysis stage of chronic kidney disease, where adherence to protein restriction was emphasized. This study did not examine the long-term prognosis of kidney function. A larger longitudinal study is needed to further validate our findings.\u003c/p\u003e"},{"header":"Conclusions","content":"\u003cp\u003eThe results of this study suggest that both low and high protein intake during the first year post-transplant may negatively impact kidney function at 1 year. Our findings indicate that evaluating protein intake during the first year post-transplant could help maintain better control of eGFR at the 1-year mark. Evidence regarding protein intake after kidney transplantation is extremely limited. Therefore, the results of this study will contribute to determining the appropriate protein intake for post-transplant patients.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eIBW\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eideal body weight\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eeGFR\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eestimated glomerular filtration rate\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eCKD\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003echronic kidney disease\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eBUN\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eblood urea nitrogen\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eLDL\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003elow-density lipoprotein\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eHbA1c\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ehemoglobin A1c\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eCRP\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eC-reactive protein\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eARB\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eangiotensin II receptor blocker\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eTAC\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003etacrolimus\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eCsA\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ecyclosporine\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eMMF\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003emycophenolate mofetil\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eEVR\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eeverolimus\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eORs\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003eodds ratios\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eCis\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003econfidence intervals\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv class=\"DefinitionListEntry\"\u003e\u003cdiv class=\"Term\"\u003eDM\u003c/div\u003e\u003cdiv class=\"Description\"\u003e\u003cp\u003ediabetes mellitus\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthical approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll procedures were performed in accordance with the ethical standards of our institution and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe institutional review board of Kitasato University Hospital waived the need to obtain informed consent from the patients because of the retrospective study design.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData sharing is not applicable to this article as no datasets were generated or analysed during the current study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll of the authors declare no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors did not receive support from any organization for the submitted work.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAT1, AT2, MY, YT, IY, NF, KK, ID, YK, and TY treated the patient. AT1, AT2, MK drafted the manuscript. AT1, AT2, MK, and TY discussed the case. AT2, MK and TY revised the manuscript critically.\u003c/p\u003e\n\u003cp\u003eAll authors approved the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors sincerely thank all study participants and the personnel at Kitasato university hospital who were involved in data collection.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eNagaoka Y, Onda R, Sakamoto K, Izawa Y, Kono H, Nakagawa K, et al. Dietary intake in Japanese patients with kidney transplantation. 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Heliyon. 2025;11(1):e40566. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/j.heliyon.2024.e40566\u003c/span\u003e\u003cspan address=\"10.1016/j.heliyon.2024.e40566\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"kidney transplantation, protein intake, eGFR slope, kidney graft function","lastPublishedDoi":"10.21203/rs.3.rs-7148397/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7148397/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eThe optimal protein intake following kidney transplantation remains unclear. The rate of change in kidney function during the first year post-transplant is considered a predictor of the subsequent survival and graft survival rates. This study aimed to determine the effect of evaluating protein intake during the first year post-transplant on kidney function at 1 year.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eThis retrospective study included 90 patients who underwent kidney transplantation. Patients were classified into three groups based on average daily protein intake: low (\u0026lt;\u0026thinsp;0.9 g/kg ideal body weight (IBW)/day), middle (\u0026ge;\u0026thinsp;0.9 and \u0026lt;\u0026thinsp;1.2 g/kg IBW/day) IBW/day), high (\u0026ge;\u0026thinsp;1.2 g/kg IBW/day). The primary outcome was the eGFR slope at 1 year after transplantation, and the secondary outcome was the incidence of rapid eGFR decline at 1 year after transplantation.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eMean eGFR slope (mL/min/1.73 m\u003csup\u003e2\u003c/sup\u003e/year) at 1 year after kidney transplantation was \u0026minus;\u0026thinsp;0.89, 2.44, and \u0026minus;\u0026thinsp;3.56 in the low, middle, and high protein intake groups, respectively (p\u0026thinsp;=\u0026thinsp;0.01). Low protein intake had a greater effect than middle protein intake on eGFR slope decline (odds ratio (OR) 3.12, 95% confidence interval (CI) 1.24\u0026ndash;7.84, p\u0026thinsp;=\u0026thinsp;0.02). Rapid eGFR slope decline was more common in the high protein intake group (62.5%, p\u0026thinsp;\u0026lt;\u0026thinsp;0.01) and high protein intake was a greater risk factor than middle protein intake (OR 22.4, 95%CI 3.21\u0026ndash;157, p\u0026thinsp;\u0026lt;\u0026thinsp;0.01).\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003eBoth low and high protein intake may adversely affect kidney function at 1 year after kidney transplantation. Evaluating protein intake during the first year post-transplant may help optimize eGFR at the 1-year mark.\u003c/p\u003e","manuscriptTitle":"Impact of Protein Intake on eGFR Slope One Year Post Kidney Transplantation: A Single- center Retrospective Study","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-27 10:59:36","doi":"10.21203/rs.3.rs-7148397/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"b6db39db-6e85-4bc2-8d4e-462075a9fd1f","owner":[],"postedDate":"July 27th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-08-27T00:08:17+00:00","versionOfRecord":[],"versionCreatedAt":"2025-07-27 10:59:36","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7148397","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7148397","identity":"rs-7148397","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}